Total Nevus Count Research Articles

Acral Melanocytic Nevi in a High-Risk Population: Prevalence, Clinical Characteristics and Dermatoscopic Patterns

Background: The prevalence of acral nevi and their dermatoscopic patterns have been mainly studied in Asian populations. Few data exist on the prevalence and clinico-dermatoscopic morphology of acral nevi in white populations. Objectives: The aim of this study was to assess the prevalence of acral nevi and evaluate their features in a cohort of Caucasian individuals at high risk for skin cancer. Methods: We prospectively examined the palms and soles of 680 high-risk patients who underwent total body clinical and dermatoscopic documentation, as a part of their routine follow-up, between January 2016 and March 2020 at a skin cancer referral center in Greece. Results: Overall, 334 acral lesions were detected in 217 (37.0%) of 585 patients in the study. The presence of acral nevi was associated with 2.6 higher odds of a total nevus count higher than 50 (OR: 2.6, p < 0.05, confidence intervals [CI]: 1.11–6.09). Of 334 acral nevi, 65.0% were clinically flat and 35.0% were clinically palpable. Palpable lesion had 19-fold higher probability of being located on the sole (OR: 19.44, p < 0.05, CI: 3.91–96.7). The parallel furrow pattern was present in 147 lesions (44.0%). In 76 lesions (22.8%), we observed a previously undefined pattern consisting of wavy lines, which was correlated with clinically palpable lesions (p < 0.001). The third most common pattern was homogeneous (10.5%), followed by the fibrillar (8.7%), the lattice-like (7.2%), the reticular (3.6%), and globular (3.3%). Conclusion: We observed a higher prevalence of benign acral melanocytic lesions than expected, probably related to our cohort selection of patients at high risk for developing skin cancer. Our study confirms the previously described dermatoscopic patterns and provides novel insights into the dermatoscopic morphology of acral palpable nevi, for which we described a new benign pattern consisting of wavy lines.

Indications for Digital Monitoring of Patients With Multiple Nevi: Recommendations from the International Dermoscopy Society.

In patients with multiple nevi, sequential imaging using total body skin photography (TBSP) coupled with digital dermoscopy (DD) documentation reduces unnecessary excisions and improves the early detection of melanoma. Correct patient selection is essential for optimizing the efficacy of this diagnostic approach. The purpose of the study was to identify, via expert consensus, the best indications for TBSP and DD follow-up. This study was performed on behalf of the International Dermoscopy Society (IDS). We attained consensus by using an e-Delphi methodology. The panel of participants included international experts in dermoscopy. In each Delphi round, experts were asked to select from a list of indications for TBSP and DD. Expert consensus was attained after 3 rounds of Delphi. Participants considered a total nevus count of 60 or more nevi or the presence of a CDKN2A mutation sufficient to refer the patient for digital monitoring. Patients with more than 40 nevi were only considered an indication in case of personal history of melanoma or red hair and/or a MC1R mutation or history of organ transplantation. Our recommendations support clinicians in choosing appropriate follow-up regimens for patients with multiple nevi and in applying the time-consuming procedure of sequential imaging more efficiently. Further studies and real-life data are needed to confirm the usefulness of this list of indications in clinical practice.

The long-term evolution of melanocytic nevi among high-risk adults.

There is little understanding regarding the long-term natural history of melanocytic nevi among adults. The objective of the study was to describe the long-term natural history of individual nevi located on the torso of high-risk patients. All patients attending Memorial Sloan Kettering Cancer Center (MSKCC) who underwent two total body photography (TBP) sessions 15+ years apart were included ('retrospective' group). To account for a potential selection bias, we also included consecutive patients who had TBP 15+ years ago and consented to undergo follow-up TBP ('prospective' group). We compared baseline and follow-up torso images on the TBPs and evaluated the number of total, new and disappearing nevi; number of seborrheic keratoses and actinic keratoses; each nevus' diameter at both time points; each nevus' colour change; the presence of clinical atypia; and when dermoscopy was available, the dermoscopic features at each time point. One hundred six patients were included in the study. Although the average age of the patients was 40 at baseline TBP, most patients developed new nevi between imaging sessions (median 16.4 years) with an average of 2.6 (SD = 4.8) nevi per participant. The average number of disappearing nevi was 0.3 (SD = 0.6). In addition, 62/106 (58%) patients had an absolute increase, and 9/106 (8%) patients had an absolute decrease in their total nevus count. Roughly half (49%: 1416/2890) of the nevi that could be evaluated at both time points increased in diameter by at least 25%. Only 6% (159/2890) of nevi shrunk in diameter by at least 25%. Patients with a history of melanoma had a higher rate of disappearing nevi, and their nevi were more likely to grow. Most nevi demonstrated no significant dermoscopic changes. High-risk patients acquire new nevi throughout life with very few nevi disappearing over time. Contrary to prior reports, most nevi in adults increase in diameter, while few nevi shrink.

Are we born and do we die without nevi? A cross-sectional study.

It is well known that the number of nevi varies with age. However, there are a few data in the literature concerning total nevus count at different ages. The aim of this study was to assess and compare the total nevus count among different age groups. The total nevus count was assessed in consecutive patients belonging to nine age groups. Median nevus count was calculated and compared for each age group. Multivariate logistic regression analysis was used to define the influence of sex and phototype on the association between nevus count and age. We enrolled 900 patients (461, 51.2% females), with a median age of 46years and a total of 18,136 nevi. Significant differences were found in the median total nevus count among all age groups (P<0.001), with a significant increase in the first two decades and a significant decrease after the age of 50years. A similar trend was also observed in subgroups. The differences observed in the total body nevus count among age groups were independent of sex and phototype. We demonstrate that the total nevus count significantly increases during childhood and gradually decreases in the elderly.

Is rituximab therapy a risk factor for development of melanoma?

In the literature, there are reports about dermoscopic and size changes of nevi in patients undergoing biologic therapy and chemotherapeutics. There has not been any established data for melanoma and Rituximab therapy. Sixteen patients, with 94 nevi were included in this study. Dermoscopic images of follow-up visits, which were performed at baseline, 3, 6, and 12 months after treatment, were evaluated. Suspicious lesions were excised. There was no increase in total nevus count. Although 61.7% of the 94 nevi have shown a stable duration without size changes, 26.5% had enlarged, and 11.7% had become smaller during our 1-year experience of dermoscopic monitoring. There was not any pattern transformation. Atypical dots and clods appeared in 17% of nevi. All of the excised nevi were comparable with Clark nevi, there was no clue for melanoma development. According to our results, we found that Rituximab therapy influences nevus morphology, but there is no evidence that this was linked to melanoma development.

Factors Related to Nevus-Associated Cutaneous Melanoma: A Case-Case Study

A proportion of cutaneous melanomas display neval remnants on histologic examination. Converging lines of epidemiologic and molecular evidence suggest that melanomas arising from nevus precursors differ from melanomas arising de novo. In a large, population-based study comprising 636 cutaneous melanomas subjected to dermatopathology review, we explored the molecular, host, and environmental factors associated with the presence of neval remnants. We found that nevus-associated melanomas were significantly associated with younger age at presentation, non-brown eye color, trunk site, thickness of less than 0.5 mm, and BRAFV600E mutation. Compared with patients with de novo melanomas, those with nevus-associated tumors were more likely to self-report many moles on their skin as a teenager (odds ratio= 1.94, 95% confidence interval= 1.01-3.72) but less likely to report many facial freckles (odds ratio= 0.49, 95% confidence interval= 0.25-0.96). They also had high total nevus counts (odds ratio= 2.18, 95% confidence interval= 1.26-3.78). On histologic examination, nevus-associated melanomas exhibited less dermal elastosis in adjacent skin compared with de novo melanomas (odds ratio= 0.55, 95% confidence interval= 0.30-1.01). These epidemiologic data accord with the emerging molecular paradigm that nevus-associated melanomas arise through a distinct sequence of causal events that differ from those leading to other cutaneous melanomas.

Factors in Early Adolescence Associated With a Mole-Prone Phenotype in Late Adolescence

ImportanceNevi are important phenotypic risk factors for melanoma in adults. Few studies have examined the constitutional and behavioral factors associated with a mole-prone phenotype in adolescents.ObjectiveTo identify host, behavioral, and dermoscopic factors in early adolescence (age, 14 years) that are associated with a mole-prone phenotype in late adolescence (age, 17 years).Design, Setting, and ParticipantsA prospective observational cohort study from the Study of Nevi in Children was conducted from January 1, 2009, to December 31, 2014, with a 2- to 3-year follow-up. A total of 569 students from the school system in Framingham, Massachusetts, were enrolled in the 8th or 9th grade (baseline; mean [SD] age, 14.4 [0.7] years). The overall retention rate was 73.3%, and 417 students were reassessed in the 11th grade.Main Outcome and MeasuresMole-prone phenotype in the 11th grade, defined as total nevus count of the back and 1 randomly selected leg in the top decile of the cohort or having any nevi greater than 5 mm in diameter.ResultsOf the 417 students assessed at follow-up in the 11th grade (166 females and 251 males; mean [SD] age, 17.0 [0.4] years), 111 participants (26.6%) demonstrated a mole-prone phenotype: 69 students (62.2%) with 1 nevus greater than 5 mm in diameter, 23 students (20.7%) with total nevus count in the top decile, and 19 students (17.1%) with both characteristics. On multivariate analysis, baseline total nevus count (adjusted odds ratio, 9.08; 95% CI, 4.0-23.7; P < .001) and increased variability of nevus dermoscopic pattern (adjusted odds ratio, 4.24; 95% CI, 1.36-13.25; P = .01) were associated with a mole-prone phenotype.Conclusions and RelevanceThis study found clinically recognizable factors associated with a mole-prone phenotype that may facilitate the identification of individuals at risk for melanoma. These findings could have implications for primary prevention strategies and help target at-risk adolescents for higher-intensity counseling about sun protection and skin self-examination.

Total Nevi, Atypical Nevi, and Melanoma Thickness: An Analysis of 566 Patients at 2 US Centers.

Nevi are among the strongest risk factors for melanoma. However, little is known about the association of many total nevi (TN) or atypical nevi (AN) with tumor thickness. To examine the association between age and the number of TN and AN and to explore whether there was a relationship between TN or AN and tumor thickness, controlling for multiple variables. Survey of patients with melanoma at 2 academic sites and an affiliated Veteran Affairs medical center. Participants included 566 patients surveyed within 3 months of diagnosis. Patients were surveyed in the melanoma clinics from May 17, 2006, through March 31, 2009, within 3 months of diagnostic biopsy. The dates of the analysis were April 1, 2015, to August 1, 2015. Counts of TN and AN were performed at the first visit after diagnosis and were categorized as 0 to 20, 20 to 50, or more than 50 for TN and as 0, 1 to 5, or more than 5 for AN. Tumor thickness was categorized as 2.00 mm or less or as 2.01 mm or greater. All analyses were stratified by patient age (<60 or ≥60 years). Logistic regression was used to test associations, controlling for age, sex, anatomic location of melanoma, institution, histologic subtype, marital status, performance of skin self-examination, number of health care visits in the past year, mode of melanoma discovery, and receipt of skin examination by a physician. The study population included 566 patients. Their mean (SD) age was 56.7 (15.9) years, and 39.0% (n = 221) were female. Of 566 patients, the number of TN was classified as 0 to 20 (66.4% [n = 376]), 20 to 50 (20.5% [n = 116]), or more than 50 (13.1% [n = 74]). Atypical nevus counts were 0 (73.3% [n = 415]), 1 to 5 (14.5% [n = 82]), or more than 5 (12.2% [n = 69]). For those younger than 60 years, the presence of more than 50 TN was associated with a sharply reduced risk of thick melanoma (odds ratio, 0.32; 95% CI, 0.12-0.81), and the presence of more than 5 AN compared with no AN was associated with thicker melanoma (odds ratio, 2.43; 95% CI, 1.02-5.75). Most patients with melanoma had few nevi and no AN. In younger patients (<60 years), thick melanomas were commonly found in those with fewer TN but more AN, suggesting that physicians and patients should not rely on the total nevus count as a sole reason to perform skin examinations or to determine a patient's at-risk status. Younger patients should be educated on the increased risk of thicker melanomas that is associated with having more AN.

Pigmentary Markers in Danes--Associations with Quantitative Skin Colour, Nevi Count, Familial Atypical Multiple-Mole, and Melanoma Syndrome.

To investigate whether pigmentation genes involved in the melanogenic pathway (melanogenesis) contributed to melanoma predisposition, we compared pigmentary genetics with quantitative skin pigmentation measurements, the number of atypical nevi, the total nevus count, and the familial atypical multiple mole and melanoma (FAMMM) syndrome. We typed 32 pigmentary SNP markers and sequenced MC1R in 246 healthy individuals and 116 individuals attending periodic control for malignant melanoma development, 50 of which were diagnosed with FAMMM. It was observed that individuals with any two grouped MC1R variants (missense, NM_002386:c. 456C > A (p.TYR152*), or NM_002386:c.83_84insA (p.Asn29Glnfs*14) had significantly (p<0.001) lighter skin pigmentation of the upper-inner arm than those with none or one MC1R variant. We did not observe any significant association of the MC1R variants with constitutive pigmentation measured on the buttock area. We hypothesize that the effect of MC1R variants on arm pigmentation is primarily reflecting the inability to tan when subjected to UVR. A gender specific effect on skin pigmentation was also observed, and it was found that the skin pigmentation of females on average were darker than that of males (p<0.01). We conclude that MC1R variants are associated with quantitative skin colour in a lightly pigmented Danish population. We did not observe any association between any pigmentary marker and the FAMMM syndrome. We suggest that the genetics of FAMMM is not related to the genetics of the pigmentary pathway.

Interactions between ultraviolet light and MC1R and OCA2 variants are determinants of childhood nevus and freckle phenotypes.

Melanocytic nevi (moles) and freckles are well known biomarkers of melanoma risk, and they are influenced by similar UV light exposures and genetic susceptibilities to those that increase melanoma risk. Nevertheless, the selective interactions between UV exposures and nevus and freckling genes remain largely undescribed. We conducted a longitudinal study from ages 6 through 10 years in 477 Colorado children who had annual information collected for sun exposure, sun protection behaviors, and full body skin exams. MC1R and HERC2/OCA2 rs12913832 were genotyped and linear mixed models were used to identify main and interaction effects. All measures of sun exposure (chronic, sunburns, and waterside vacations) contributed to total nevus counts, and cumulative chronic exposure acted as the major driver of nevus development. Waterside vacations strongly increased total nevus counts in children with rs12913832 blue eye color alleles and facial freckling scores in those with MC1R red hair color variants. Sunburns increased the numbers of larger nevi (≥2 mm) in subjects with certain MC1R and rs12913832 genotypes. Complex interactions between different UV exposure profiles and genotype combinations determine nevus numbers and size, and the degree of facial freckling. Our findings emphasize the importance of implementing sun-protective behavior in childhood regardless of genetic make-up, although children with particular genetic variants may benefit from specifically targeted preventive measures to counteract their inherent risk of melanoma. Moreover, we demonstrate, for the first time, that longitudinal studies are a highly powered tool to uncover new gene-environment interactions that increase cancer risk.

Twenty nevi on the arms

Patients with a high total nevus count (TNC) merit a total-body examination, but a simple strategy to identify these high-risk individuals is essentially missing. The aim of this study was to investigate the correlation between the number of melanocytic nevi on both arms and the TNC, and to evaluate patient variables that may have an effect on this association. In this multicenter, cross-sectional study, 2175 patients were examined and the mean number of arm nevi in relation to TNC was calculated. A mean value of fewer than 10 arm nevi was found in patients with TNC lower than 51 and a mean value of greater than 19 arm nevi was scored in patients with TNC greater than 50. These values remained unchanged after adjustment for various patient variables. In relation to TNC greater than 50, the presence of 20 or more arm nevi had specificity and negative predictive values of 95.2 and 89.6%, respectively. The sensitivity was 65.5% in patients younger than 50 years of age and 37.5% in the older age group. The number of arm nevi was significantly higher in individuals with a history of melanoma and in those with a melanoma detected during the study period. The presence of 20 or more nevi on the arms is an independent predictor of a high TNC and risk of melanoma. This sign thus represents a simple and rapid screening tool for either the primary care physician or the dermatologist to help identify high-risk patients.

Phenotypic Characterization of Nevus and Tumor Patterns in MITF E318K Mutation Carrier Melanoma Patients

A germline polymorphism of the microphthalmia transcription factor (MITF) gene encoding a SUMOylation-deficient E318K-mutated protein has recently been described as a medium-penetrance melanoma gene. In a clinical assessment of nevi from 301 volunteers taken from Queensland, we identified six individuals as MITF E318K mutation carriers. The phenotype for 5 of these individuals showed a commonality of fair skin, body freckling that varied over a wide range, and total nevus count between 46 and 430; in addition, all were multiple primary melanoma patients. The predominant dermoscopic signature pattern of nevi was reticular, and the frequency of globular nevi in carriers varied, which does not suggest that the MITF E318K mutation acts to force the continuous growth of nevi. Excised melanocytic lesions were available for four MITF E318K carrier patients and were compared with a matched range of wild-type (WT) melanocytic lesions. The MITF staining pattern showed a predominant nuclear signal in all sections, with no significant difference in the nuclear/cytoplasmic ratio between mutation-positive or -negative samples. A high incidence of amelanotic melanomas was found within the group, with three of the five melanomas from one patient suggesting a genetic interaction between the MITF E318K allele and an MC1R homozygous red hair color (RHC) variant genotype.

Indicators for the total number of melanocytic naevi: an adjunct for screening campaigns. Observational study on 292 patients

The presence of multiple melanocytic naevi is a strong risk factor for melanoma. Use of the whole body naevus count to identify at-risk patients is impractical. To (i) identify a valid anatomical predictor of total naevus count; (ii) determine the number of naevi that most accurately predict total naevus count above 25, 50 and 100; and (iii) evaluate determinants of multiple melanocytic naevi and atypical naevi. Clinical data from 292 consecutive Spanish patients consulting for skin lesions requiring debriding were collected throughout 2009 and 2010. Correlations between site-specific and whole body naevus counts were analysed. Cut-offs to predict total naevus counts were determined using the area under the receiver operating characteristic curve. The studied population was young (median age 31 years, interquartile range 28-43). The naevus count on the right arm correlated best with the total nevus count (R(2) 0.80 for men, 0.86 for women). Presence of at least five naevi on the right arm was the strongest determinant of a total naevus count above 50 [odds ratio (OR) 34.4, 95% confidence interval (CI) 13.9-85.0] and of having at least one atypical naevus (OR 5.7, 95% CI 2.4-13.5). Cut-off values of 6, 8 and 11 naevi on the right arm best predicted total naevus count above 25, 50 and 100, respectively. Our results support the arm as a practical and reliable site to estimate the total naevus count when screening or phenotyping large populations. Threshold values for the number of naevi on the arm are proposed to help identify patients for melanoma screening.

Expression of cyclins A and E in melanocytic skin lesions and its correlation with some clinicopathologic features

Cyclins play a fundamental role in the cell cycle. Recent studies have focused on their role in the development of various malignancies. The objective of this study was to evaluate and compare the expression of cyclins A and E in common nevi, dysplastic nevi and malignant melanomas, and to investigate the relationship between cyclin expression and some pathological parameters such as tumor thickness, ulceration, regression, and mitotic rate, as well as several clinical and phenotypic parameters such as skin phototype, hair and eye color, number of nevi, personal or family melanoma history, and personal history of nonmelanoma skin cancer (NMSC). A total of 102 melanocytic skin lesions, including 30 common nevi, 38 dysplastic nevi and 34 melanomas, were examined. Expression of cyclins was detected by immunohistochemistry and quantified as a percentage of immunostained cell nuclei in each sample. Significant differences in expression of both cyclins were found between all lesion types: the median percentage of cyclin A-positive nuclei was 8.2% in melanomas, 3.4% in dysplastic nevi, and 0.95% in common nevi (p &lt; 0.001). The corresponding percentages for cyclin E were 9.5%, 4.25% and 1.44% (p &lt; 0.001). Expression of both cyclins was significantly higher among patients with a personal history of NMSC. Cyclin A was also significantly overexpressed in patients with a high total nevus count (TNC) compared to moderate and low TNC. Expression of cyclins did not significantly correlate with the other clinicopathologic features investigated. These findings indicate the possible involvement of cyclins A and E in the pathogenesis of malignant melanoma. Our results also show a potential diagnostic significance of these cyclins as markers allowing discrimination between dysplastic nevi and melanoma.

Study of Nevi in Children (SONIC): Baseline Findings and Predictors of Nevus Count

The authors report baseline findings and predictors of nevus count (log total nevi) at the completion of year 1 (2004) of the first known population-based, prospective study of nevi in a US cohort of children. Overall, 64% (n = 443/691) of grade 5 students and their parents in Framingham, Massachusetts, completed surveys and underwent digital photography. Total nevus count was associated with skin and hair color and tendency to burn, as measured by a sun sensitivity index. In multivariate analyses, male gender (rate ratio (RR) = 1.38, 95% confidence interval (CI): 1.22, 1.55; P < 0.0001), spending 5-6 weekly hours outdoors between 10 AM and 4 PM (RR = 1.13, 95% CI: 1.00, 1.28; P = 0.051), getting a painful sunburn once (RR = 1.24, 95% CI: 0.98, 1.57; P = 0.073) and at least twice (RR = 1.34, 95% CI: 0.99, 1.82; P = 0.061), and wearing a shirt at the beach or pool rarely (RR = 1.29, 95% CI: 1.08, 1.54; P = 0.005), sometimes (RR = 1.26, 95% CI: 1.01, 1.57; P = 0.041), and often and always (RR = 1.32, 95% CI: 1.13, 1.54; P = 0.001) were associated with increased number of nevi. Identifying factors that predict the development of nevi will improve primary prevention efforts during early life.

Nevus Count on Specific Anatomic Sites as a Predictor of Total Body Count: A Survey of 3,406 Children from Italy

Scanty information is available on the relation between nevus count on specific anatomic areas and the total body surface, particularly in children. The authors analyzed this issue by using data from a uniquely large study conducted in 1997 on 3,406 schoolchildren (1,746 boys and 1,660 girls) aged 13-14 years in 13 cities from northern, central, and southern Italy. Children were examined by trained dermatologists who counted melanocytic nevi (>or=2 mm in diameter) on 19 different anatomic sites. Overall, the mean number of nevi was 17.3 (18.6 in boys and 15.8 in girls). The adjusted correlation coefficients (r) with number of nevi on the whole body were 0.74 for head and neck, 0.83 for anterior and 0.84 for posterior trunk, and 0.88 for upper and 0.80 for lower limbs. With reference to single anatomic sites, the best predictor of total nevus count was the lateral arms (r=0.80), overall and in strata of sex and pigmentary characteristics. This large study provides definite evidence that examining the upper limbs only, particularly the lateral arms, is a practical and suitable tool for predicting total nevus count in children.

The role of host factors in predicting total back nevus count in adolescents: Results from the Framingham SONIC study

The role of host factors in predicting total back nevus count in adolescents: Results from the Framingham SONIC study

Effect of Neonatal Phototherapy on Melanocytic Nevus Count in Children

Melanocytic nevus is the strongest risk factor for the development of cutaneous melanoma. Fair skin and exposure to UV light, especially in childhood, are correlated with the development of childhood nevi. To assess the role of blue light neonatal phototherapy used to treat hyperbilirubinemia in nevus acquisition in childhood. Case-control prospective study. University hospital. Fifty-eight children were included in this study. Selection criteria included the following: age, 8 to 9 years; and skin type, less than IV by Fitzpatrick classification (ie, brown, always tans, rarely burns). The case group consisted of 18 children exposed to neonatal phototherapy (mostly intensive phototherapy) retrospectively found by review of consecutive neonatal medical records at Saint-Antoine Hospital, Paris, France. The control group was composed of 40 nonexposed children consecutively recruited from a public school in the same geographic area. Total body nevus count in children, phenotypic characteristics, solar exposure, and demographic data were assessed by the same dermatologist. A comparison of both groups showed that the number of nevi larger than 2 mm was significantly higher in the exposed group. The mean (SD) nevus count was 3.5 (3.05; median, 3.0) per child in the exposed group, compared with 1.45 (1.99; median, 1.0) per child in the nonexposed group (P(mean) = .02 and P(median) = .01). Multivariate analysis confirmed these results, with a statistically significant correlation with nevus count, especially with nevi 2 to 5 mm in greatest diameter. The association between neonatal phototherapy and nevus count was not significant for nevi smaller than 2 mm or larger than 5 mm. Solar exposure, especially during vacations, was strongly associated with total nevus count and all nevus sizes (2-5 mm, <2 mm, and >5 mm). At univariate analysis, hair color was significantly associated with nevus size smaller than 2 mm (P(mean) = .03). Intensive neonatal phototherapy is a strong risk factor for nevus development in childhood. While childhood development of nevi is correlated with fair skin and solar light exposure, and having many nevi is a recognized risk factor in persons with melanoma, we must be careful not to equate childhood nevi development in response to neonatal phototherapy with an individual's risk of developing melanoma. The treatment of hyperbilirubinemia remains neonatal phototherapy. Exposed children should undergo dermatologic preventive measures and surveillance for the development of melanoma.

Melanocytic nevi in very young children: The role of phenotype, sun exposure, and sun protection

Melanocytic nevi are strongly associated with cutaneous melanoma, yet little is known about factors influencing nevus development in the first years of life. We sought to identify phenotypic and environmental factors associated with nevus counts in very young children. In a cluster prevalence survey, full body nevus counts and phenotypic assessments were conducted on 193 children aged 1 to 3 years. Information on each child's sun exposure and sun protection practices was obtained through parental questionnaire. High total nevus counts were associated with heavy facial freckling, time spent outdoors on weekends in summer, and Caucasian ethnicity. Low nevus counts were associated with dark skin color, ability to tan, and frequent application of sunscreen. Frequent wearing of hats was specifically associated with low nevus counts on the face, but not at other sites. Nevi are common at a very young age among children in Queensland, Australia, and are associated with sun exposure and freckling. Diligent sun protection practices appear to reduce nevus burden, even after accounting for the effects of phenotype and sun exposure factors. Primary prevention strategies aimed at reducing sun exposure in very early life may be effective in reducing nevus prevalence and melanoma risk.

Genetics of risk factors for melanoma: an adult twin study of nevi and freckles.

We sought by use of an adult twin study to investigate the relative contribution of genetic and environmental effects on the expression of nevi and freckles, which are known risk factors for melanoma, and to determine if age and sun exposure influence the heritability of nevi. Total nevus and freckle counts were conducted on 127 monozygotic twin pairs and 323 dizygotic twin pairs. Intraclass correlations were calculated by use of analysis of variance. Model-fitting analyses were performed to quantify the genetic and environmental components of the variance for nevus and freckle counts. The intraclass correlation for total nevus counts was.83 in monozygotic pairs compared with.51 in dizygotic pairs. Quantitative genetic analyses showed that the contribution of genetic factors on nevi expression varied according to age. For twins less than 45 years old, the additive genetic variance on total nevus count was 36% (95% confidence interval [CI] = 0.8%-63%), with 38% (95% CI = 14%-61%) and 26% (95% CI = 16%-42%) of the remaining variance attributed to common environment and unique environmental effects, respectively. In twins aged 45 years or older, common environmental effects on total nevus count became negligible, with the additive genetic variance increasing to 84% (95% CI = 77%-88%). Body site was also found to affect the heritability estimates for nevus counts, with a statistically significant difference between sun-exposed and sun-protected sites. The polychoric correlation (i.e., the correlation in liability within twins for more than two categories) for total freckle counts was.91 in monozygotic twin pairs compared with.54 in dizygotic twin pairs. Additive genetic effects explained 91% (95% CI = 86%-94%) of the variance in freckle counts. The contribution of genetic factors on the variance for total nevus counts increased with age, and sun exposure appears to influence the expression of nevi. The results of this study highlight the need to take into account the age and site of nevus counts for future genetic linkage or association studies in the search for new melanoma genes.